Radiolabelled feeding experiments with L-ascorbic acid (AsA) precursor substrates. Uptake and conversion of 14C in immature green, mature green and red fruit discs of ‘Santorini’ (white) and ‘Ailsa Craig’ (gray) after incubations for 24 hours with 1 μCi L-[6-14C]AsA (I), [U-14C]D-Mannose (U-14C]D-Man; II) and [U-14C]D-Glucose (U-14C]D-Glc; III). Results are represented as total radiolabel (μCi) recovered in tissues (A), and as total radiolabel (μCi) incorporated into total 14C-AsA (B). Data show the mean ± SD of three independent experiments. Different letters indicate significant differences (P < 0.05) between values based on Duncan's multiple-range-test in SAS.